1. Field of the Invention
This invention relates to a blood testing method for early detection of diseases.
2. Description of Prior Art
Biochemical analysis of a body fluid such as blood is currently increasingly conducted for diagnosing various sicknesses in many hospitals. In the case of diagnosis of diabetes, for example, blood samples before and after meal are generally analyzed for the concentration of glucose therein.
Glucose is a source of energy for human body's cells and is released from the liver into blood. In a healthy individual, the release of glucose from the liver and the utilization of glucose in the cells are balanced so that the blood glucose level is maintained at about 110 mg/dL or less. Insulin is a hormone secreted from pancreas and necessary for the human body to properly convert sugar, starches and other food into a cellular energy source. When starch is digested in the small intestine, the level of glucose present in the blood increases. Such an increase in the blood glucose level stimulates increased secretion of insulin so that the liver stops releasing the glucose. Upon intracellular utilization of the glucose, the blood glucose decreases to the normal level. Such increase and decrease of the blood glucose level are repeated every time a healthy individual takes foods.
Some individuals are unable to quickly or sufficiently secrete insulin even when their blood glucose level rises after meal. When insufficient exercise and excess ingestion are added to this condition, glucose remains excessively in blood so that the blood glucose level does not decrease even after several hours from the intake of meals.
In the conventional biochemical analysis, the blood glucose level is measured by isolating plasma from blood samples taken before and after meals. When the glucose concentration in a plasma sample obtained in an empty stomach stage is greater than 140 mg/dL or when the glucose concentration in a plasma sample taken just after meal is greater than 200 mg/dL, then he or she is diagnosed as being diabetic (type-2 diabetes). A high glucose level when continued for a long time will cause heart, circulation, eye and kidney problems.
There are recent reports concerning symptoms of cardiac infarction in individuals whose blood glucose levels were found to be not significantly high when measured with the conventional plasma test method. Namely, it has been found that arteriosclerosis proceeds even in prediabetics. Especially, individuals whose insulin secretion is slow are likely to cause arteriosclerosis when they meet with one or more conditions of mild type-2 diabetes, slight overweight, mild hyperlipidemia and light hyperinsulinemia. The conventional blood test methods in which plasma of a blood sample is measured for the concentration of glucose is not effective for the early detection of diabetes. Thus, there is an urgent demand for a diagnostic method capable of precisely detecting diabetes and other diseases even at their early stages.